﻿using System;
using System.IO; 
using System.Security.Cryptography;

namespace Crypto
{
    public class Cryptor
    {
        public static byte[] Encrypt(byte[] clearData, byte[] Key, byte[] IV)
        {
            MemoryStream ms = new MemoryStream();
            Rijndael alg = Rijndael.Create();

            alg.Key = Key;
            alg.IV = IV;

            CryptoStream cs = new CryptoStream(ms, alg.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(clearData, 0, clearData.Length);
            cs.Close();

            byte[] encryptedData = ms.ToArray();

            return encryptedData;
        }

        public static string Encrypt(string clearText, string Password)
        {
            byte[] clearBytes = System.Text.Encoding.Unicode.GetBytes(clearText);

            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});

            byte[] encryptedData = Encrypt(clearBytes, pdb.GetBytes(32), pdb.GetBytes(16));

            return Convert.ToBase64String(encryptedData);
        }

        public static byte[] Encrypt(byte[] clearData, string Password)
        {
            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});

            return Encrypt(clearData, pdb.GetBytes(32), pdb.GetBytes(16));
        }

        public static void Encrypt(string fileIn, string fileOut, string Password)
        {
            FileStream fsIn = new FileStream(fileIn, FileMode.Open, FileAccess.Read);
            FileStream fsOut = new FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write);

            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});

            Rijndael alg = Rijndael.Create();
            alg.Key = pdb.GetBytes(32);
            alg.IV = pdb.GetBytes(16);

            CryptoStream cs = new CryptoStream(fsOut, alg.CreateEncryptor(), CryptoStreamMode.Write);

            int bufferLen = 4096;
            byte[] buffer = new byte[bufferLen];
            int bytesRead;

            do
            {
                bytesRead = fsIn.Read(buffer, 0, bufferLen);

                cs.Write(buffer, 0, bytesRead);
            } while (bytesRead != 0);

            cs.Close();
            fsIn.Close();
        }

        public static byte[] Decrypt(byte[] cipherData, byte[] Key, byte[] IV)
        {
            MemoryStream ms = new MemoryStream();

            Rijndael alg = Rijndael.Create();

            alg.Key = Key;
            alg.IV = IV;

            CryptoStream cs = new CryptoStream(ms, alg.CreateDecryptor(), CryptoStreamMode.Write);

            cs.Write(cipherData, 0, cipherData.Length);
            cs.Close();

            byte[] decryptedData = ms.ToArray();

            return decryptedData;
        }

        public static string Decrypt(string cipherText, string Password)
        {
            byte[] cipherBytes = Convert.FromBase64String(cipherText);

            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});
            
            byte[] decryptedData = Decrypt(cipherBytes, pdb.GetBytes(32), pdb.GetBytes(16));

            return System.Text.Encoding.Unicode.GetString(decryptedData);
        }

        public static byte[] Decrypt(byte[] cipherData, string Password)
        {
            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});

            return Decrypt(cipherData, pdb.GetBytes(32), pdb.GetBytes(16));
        }

        public static void Decrypt(string fileIn, string fileOut, string Password)
        {
            FileStream fsIn = new FileStream(fileIn, FileMode.Open, FileAccess.Read);
            FileStream fsOut = new FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write);

            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});
            Rijndael alg = Rijndael.Create();

            alg.Key = pdb.GetBytes(32);
            alg.IV = pdb.GetBytes(16);

            CryptoStream cs = new CryptoStream(fsOut, alg.CreateDecryptor(), CryptoStreamMode.Write);

            int bufferLen = 4096;
            byte[] buffer = new byte[bufferLen];
            int bytesRead;

            do
            {
                bytesRead = fsIn.Read(buffer, 0, bufferLen);

                cs.Write(buffer, 0, bytesRead);

            } while (bytesRead != 0);

            cs.Close(); 
            fsIn.Close();
        }
    }
}
